fix(watcher-tests): await ready + harden Windows cleanup

[PatrickSys]

What / Why

Phase 2d (auto-refresh file watcher) is merged, but a full-suite run on Windows exposed intermittent flakes that make CI/local verification unreliable:

• Watcher readiness race: writes can occur before chokidar is fully ready, causing missed change events.
• Windows cleanup race: temp directory deletion can intermittently fail with ENOTEMPTY / EPERM / EBUSY.

This PR hardens the watcher tests (and adds a tiny optional hook) so the test suite is deterministic and accurately validates 2d behavior.

Changes

• src/core/file-watcher.ts: add optional onReady?: () => void and fire it on chokidar 'ready'.
• tests/file-watcher.test.ts: wait for watcher readiness; adjust debounce test timing to avoid double-fire flakes.
• tests/auto-refresh-e2e.test.ts: wait for watcher readiness instead of sleeping.
• tests/search-snippets.test.ts: retry fs.rm on Windows + bump hook timeouts.
• tests/impact-2hop.test.ts: retry fs.rm + use os.tmpdir() for temp roots (avoid repo/gitrepo side effects + sporadic EPERM lstat).

Non-goals / Notes

• No functional/product behavior changes intended (existing watcher consumers remain compatible; onReady is optional).
• Does not address the separate Phase 2e follow-up: some --json CLI commands still print extra non-JSON to stdout.

Validation

• CI checks: Quality Checks, Functional Tests, GitGuardian all green.
• Local: pnpm test (full suite) green on Windows after these changes.

Release notes

• Minor: stabilize watcher-related tests on Windows (no user-facing change).

[greptile-apps]

Greptile Summary

This PR improves test reliability by replacing arbitrary sleep timings with deterministic ready callbacks and adding retry logic for Windows filesystem cleanup issues.

• Replaced sleep() calls with onReady callback waits in all file watcher tests
• Added rmWithRetries helper with exponential backoff for ENOTEMPTY/EPERM/EBUSY errors in 2 test files
• Adjusted debounce timings in tests for better reliability

Issues found:

• file-watcher.test.ts and auto-refresh-e2e.test.ts are missing the Windows cleanup hardening despite creating file watchers that can cause lock issues
• rmWithRetries is duplicated across multiple test files instead of being extracted to a shared utility

Confidence Score: 3/5

• Safe to merge but incomplete - Windows cleanup hardening only applied to 2 of 4 test files
• The changes are well-intentioned and improve test determinism, but the Windows cleanup hardening is incomplete. Two test files that create file watchers (file-watcher.test.ts and auto-refresh-e2e.test.ts) still use direct fs.rm calls instead of rmWithRetries, which means they could still experience flaky failures on Windows. The onReady callback implementation is solid.
• Pay close attention to tests/file-watcher.test.ts and tests/auto-refresh-e2e.test.ts - both need Windows cleanup hardening

Important Files Changed

Filename	Overview
tests/file-watcher.test.ts	Updated tests to await watcher ready event, but missing Windows cleanup hardening
tests/auto-refresh-e2e.test.ts	Replaced sleep with ready callback, but missing Windows cleanup hardening
tests/impact-2hop.test.ts	Added retry logic with exponential backoff for Windows filesystem cleanup

_{Last reviewed commit: 87e7434}

[greptile-apps]

_{5 files reviewed, 3 comments}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

consider extracting rmWithRetries to a shared test utility file since it's duplicated in search-snippets.test.ts and will likely be needed in other test files

_{Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!}

[greptile-apps]

Additional Comments (2)

tests/file-watcher.test.ts
missing Windows cleanup hardening - this test creates a file watcher and should use rmWithRetries like impact-2hop.test.ts and search-snippets.test.ts to handle Windows filesystem lock issues (ENOTEMPTY, EPERM, EBUSY)

---

tests/auto-refresh-e2e.test.ts
missing Windows cleanup hardening - this test creates a file watcher and should use rmWithRetries like impact-2hop.test.ts and search-snippets.test.ts to handle Windows filesystem lock issues (ENOTEMPTY, EPERM, EBUSY)

[PatrickSys]

Greptile feedback addressed in ebf15db: extracted
mWithRetries into ests/test-helpers.ts and used it in ests/file-watcher.test.ts + ests/auto-refresh-e2e.test.ts (and de-duplicated from the other suites). Watcher-related tests re-run locally and passing.